(1) Field of the Invention
The present invention relates to a semiconductor device, a reproduction device, and a method for controlling the same, and particularly to a method for controlling a reproduction device which reproduces data held in a USB device connected to a USB terminal.
(2) Description of the Related Art
Portable compact disc players and mini-disc players have been conventionally used as portable audio players. Recently, instead of the portable compact disc players and the mini-disc players, portable digital audio players have been on sale and accepted in the market, and their sales have been increasing. A portable digital audio player reproduces music data recorded in an internal flash memory or an external flash memory card.
The portable digital audio player includes a Universal Serial Bus (USB) terminal. The digital audio player obtains, via a USB, music data stored in a hard disk or the like of a personal computer or music data created on the personal computer. The portable digital audio player writes the obtained music data into the internal flash memory or the external flash memory card by using a USB device controller.
Generally speaking, a user often listens to music reproduced with a portable audio player, using a headphone connected to the portable audio player. On the other hand, there is an increasing demand for listening to music reproduced with the portable audio player in a room, a car, or the like where sound leakage to the surroundings does not matter, the music being outputted through a speaker of stationary audio equipment installed in the room or the car. As a result, it has been suggested that a USB used only as an interface between a personal computer and a peripheral device with a USB device function is used as an interface between the portable audio player and the stationary audio equipment. Furthermore, in response to such demand, stationary audio equipment, which is a reproduction device with a USB host function, is gradually put on sale.
A conventional reproduction device with a USB host function reads data from a storage medium with a USB device function that is connected to a USB connector (for example, a memory card and the like) or a reproduction device having a storing unit (for example, a portable digital audio player) and reproduces the read data.
In the case where a USB device is connected to the USB connector, a USB host generates a call signal and waits for a response from the USB device. The USB host determines whether or not the connected USB device includes the storing unit, based on the response from the USB device. Further, the USB host determines whether or not music data stored in the storing unit of the USB device can be reproduced and is accessed, based on the response from the USB device. In the case where the music data stored in the storing unit of the USB device can be reproduced, the USB host analyzes a file of internal record data in the storing unit, discerns a record composition, and allows read access to data to be reproduced.
The conventional reproduction device with the USB host function waits for a response from the USB device to a call generated by the USB host for a predetermined amount of time, and determines that the USB device cannot be reproduced in the case where there is no response within the predetermined amount of time (for example, refer to Japanese Unexamined Patent Application Laid-Open Publication No. 2005-519354).
Hereinafter, a conventional reproduction device is described with reference to FIG. 1.
FIG. 1 is a flow chart showing a flow of a reproduction processing for music data stored in a USB device by the conventional reproduction device.
Initially, the conventional reproduction device detects insertion of the USB device (S501). Secondary, the conventional reproduction device detects a corresponding speed of the inserted USB device (S502), and subsequently an access speed is determined according to the detected corresponding speed (S503). Next, the conventional reproduction device transmits a call command to the USB device (S504), and then waits for a response for a predetermined amount of time (S505). After a waiting time is over, the conventional reproduction device confirms whether or not there was the response from the USB device during the waiting time (S506).
In the case where there was the response (Yes in S506), the conventional reproduction device performs file analysis on the USB device, extracts files to be reproduced, based on the file analysis result, and determines a reproduction order (S507). Subsequently, the conventional reproduction device begins stream transmission of a start file of the files to be reproduced (S508), the reproduction order being assigned to the respective files, and begins to reproduce data on which the stream transmission is performed via a USB (S509).
On the other hand, in the case where there was no response in S506 (No in S506), the conventional reproduction device notifies a system controller or the like that the USB device cannot be reproduced (S510), the system controller or the like controlling an entire system, and ends a reproduction operation.
However, in the case where there is no response from the USB device to a call generated by a USB host within a predetermined amount of time, it is determined that such a USB device cannot be reproduced. As a result, the conventional reproduction device determines that even a reproducible USB device that gives a late response cannot be reproduced. In other words, an erroneous decision of whether or not the USB device can be reproduced occurs in the conventional reproduction device, depending on the response speed of the USB device.
Moreover, when the waiting time for response is set long in order to handle those that give late responses, it takes an additional time until the reproduction begins, the additional time being equivalent to the waiting time. Accordingly, this causes a problem that a time from when the USB device is connected till when the reproduction of the music data begins becomes longer, so that the waiting time for the user increases.
Consequently, the present invention has an object of providing a reproduction device and a method for controlling the reproduction device which prevent an erroneous decision of whether or not a USB device can be reproduced and suppress an increase in the waiting time until the reproduction begins.